A demon's rival

Young King Serpin is heard to be the wisest ruler, but the secret to his wisdom is a dexterous demon pretending to be the king's counselor. No one but Samantha, marked by fairies, sees the demon on the king's shoulder. Anyone who wants to become Serpin's bride must first drive the demon out of the country. Samantha is willing to take the risk, not yet knowing that the demon serves the beautiful and dangerous demon queen Luciferina, who probably also has her sights on Serpin.